Kam, I guess it depends on what you consider playable. As Black I would never set out to defend such a difficult ending. It seems to me that White has good chances to win, while the best that Black can hope for is a draw. You may be right that Black's draw is there; I myself am not so sure. Still, your analysis has the merit of showing that Black can swap off White's dangerous rooks.

The line leading to the initial diagram is already rather deep; your analysis takes us even deeper into territory where White is by no means forced to play any of the suggested moves. At some point in studying any given opening continuation, further analysis becomes much less useful than a judgment of the advantages and disadvantages faced by each side; I already gave mine. In fact I think it's a serious difficulty with a lot of machine-assisted analysis that we see these days (and I freely admit that I myself analyze with the assistance of a machine) is that it chases specificity down too many long paths, instead of stepping back and trying to apply some common sense to the position. All may be specificity in chess, but not all can be specificity when it comes to understanding chess.

One very small point is that 25.Be3 may be a stronger move than 25.Bc3, e.g. 25...Nc6 26.Rxb8 Rxb8 27.Rc7 Nd8 28.Nd4 Rb7 29.Rxb7 (29.Rxb7 after 25.Bc3 also may be worth considering) 29...Nxb7 30.c6 Nd6 31.Kc3 and White's threat to cross over the dark diagonal compels 31...Nc8, after which 32.Nb5 and Black is pretty well tied up (though White has no clear win). But this point is very minor because the position arising at move 25 isn't necessarily critical for the line.

Black must face the reality that the black rook can never be as dominating as the white counterpart and thus the forced exchange of heavy pieces is the best strategy. A possible continuation is 29.Rc8 Ne6 30.c6 Rc7! 31.Rxc7 Nxc7 32.Kd3 Ne8 33.Ba5 Bd6 34.Bb6 Ke7 35.h3 g5 ±/= etc

Kam, I salute your enthusiasm for this line and your willingness to look deeply into these interesting positions. But I couldn't help thinking, in light of so much talk in "Chess Chat" about the expression, "flogging a dead horse," that that's what you're doing here.

Here you suggest 16...dxc5 17.dxc5 Qb5 and now it seems to me that the silicon-recommended 18.Rd1 is indeed strong. After your 18...Nxa2 White plays not 19.Rxd5 but instead 19.Qxb5 Rxb5 20.Ra1and Black faces many difficulties, e.g. 20...Rxb2 21.Bd4 Rb8 22.Kd2 Nb4 23.Rhb1 and Black must cede his extra pawn, after which the ending looks very favorable to White, who will enjoy the outside passed pawn and more active rooks and king. This seems to be a feature of the endings that come up in many of your other variations as well. Or 20...Nb4 21.Rxa7 Nc2+ 22.Kd2 Nxe3 23.fxe3 Rxb2+ 24.Kd3 and not only does White still have his dangerous c-pawn, but his pieces are vastly more active than Black's. Black even has trouble with his king.

Where we differ seems to be in your saying that White is slightly better in the endings that eventually result from 16.Qe2, while I'm saying that White is much better.

The aim of the king side pawn advance is to control space on the king side, remove the threat of the back rank mate and restrict the mobility of the white king side pawns. Black has good chances of saving the game and winning can also be a serious possibility! (26...h6 27.Nd4 Rb6 28.Ra5 (28.Nf5 Nc6 29.Rd7 Rb5) 28...Kf8 29.Nf5 Rb8) 27.g3 Nc6 (27...Rb5 28.Nd4 Rb6 29.Nf5 Nc6 30.Rd7 Rb5 31.f4 Rc5+ 32.Kd2 h4 33.Nxh4 Rb5 34.Rc7 Nd4 35.Kc3 Nxb3 36.Nf5 d4+ 37.Nxd4 Nxd4 38.Kxd4 g6 39.h4 Black may be able to save this position?) 28.Rc7 d4+ Black needs to somehow exchange off his weak centre pawn. 29.Kb2 Nb4 30.Nxd4 Nd3+ 31.Kc3 Nxf2

Diagram 11.

Black has restored the material balance, but white's passed pawn is very dangerous.

The rook exchange sacrifice 14...Rxb5 is unsound, as shown by Markovich. The alternative 14....Nb4 is sufficient, despite that Markovich considers this move to be also bad. The material balance can be restored, but white is able extract a slight space advantage and black may need to play accurately against persistant positional grinding play. A crucial move is the 42... Nxb5 knight sacrifice,and white must fight to save the game. Improvements are likely to be found, but the general atmosphere of the game is instructive to how the development of the variation could procede.

Both sides have the same amount of material, but white has dangerous passed queen side pawns, which can be assisted by the white king. The black king will have limited influence on the queen side and it seems that the black king must be prepared for opportunities on the opposing flank. White can now apply the grinding method, which almost works.

I've also looked at another pawn sacrifice, Black playing 10...dxc5 11.dxc5 Nd7 12.Qxb7 Rc8. But Black doesn't get nearly enough for his pawn if White plays well.

The fundamental problem is that the early appearance of Black's QN on c6 is not good with this Old Main Line-type structure, and with 9.Qb3! White puts his finger on this.

Just lately though, I've been looking at 7...g6!? (instead of 7...e6), as played in Kalisky - Slacky, Solvakia 2008 (the players were rated 2200+ each). It seems to me that this fits in much better with the early ...Nc6.

Now interestingly, 8.exd6 cxd6 produces a position that normally arises from an Exchange Variation, and which has scored well for Black in 43 games in my database.

If instead 8.h3, then after 8...Bxf3 9.Qxf3 dxe5 10.dxe5 e6! and White has trouble defending his e-pawn. For example 11.c5 (or 11.Rd1 Nd7 or 11...Qe7) 11...Nd7 12.O-O-O a6! 13.Ne4 (or 13.h4 Qe7 or 13.Qg3 Ncxe5!) 13...Ncxe5 14.Qg3 Bg7. These ideas are very preliminary, and 8.h3 should be further investigated.

Kalisky - Slacky and Muuss - Pawlowsky both saw 9.exd6 cxd6, which again transposes into a version of the Exchange Variation that is perfectly acceptable for Black. Lorelli played more aggressively: 9.e6!? fxe6 10.Ng5 Bxe7 11.Qxe2. Here Black played 11...Nxd4? 12.Bxd4 Bxd4 and lost after 13.Nb5. Instead he has to play 11...Qd7, after which White has the burden of proof, which won't be aided by the absence of his light-square bishop. It requires further investigation, but my intuition is that Black is good.

So 7...g6!? and either 8.h3 produces an advantage for White by some means that I don't yet see, or Black is entirely fine after 4...Nc6 5.c4 Nb6 6.Nc3 Bg4 7.Be3 g6!

Alekhine Defence Haakert Variation.Comments Based on the Game Safarli-Chighladze, Baku Open 2010, Part 3.Pawn Sacrifice Against a Subtle Move Order.

I had previously concluded that after 6.Nc3 Bg4 7.Be3 e6 8.exd6 cxd6 9.Qb3 Bxf3 10.gxf3, the reply 10…. Rc8?! was insufficient for black due to the devastating 11.d5! (Linksspringer). My recommendation is to avoid the seemingly thematic 9….Bxf3 and instead calmly play the unperturbed 9…. Be7!?

Black has correctly decided not to accepted the opportunity to wreck the white king side pawn structure. Instead, black offers white a pawn! The black light square bishop may be required to return to d7 to protect a knight at c6 and block some checks along the e8-a4 diagonal in some critical variations.In the actual Safarli-Chighladze game, black played 9….Qd7 and white seized the advantage with 10.d5 +-. 10.c5 [10.d5 Bxf3 White did not play the critical 10.c5 and thus it is safe to punish white by capturing the knight at f3 and wrecking the white king side pawn structure. 11.gxf3 exd5 12.cxd5 Ne5 13.Qb5+ Ned7 14.0–0–0 0–0±/=] 10...Nd5 11.Qxb7 [11.Nxd5 exd5 12.Qxb7 Bd7 Diagram 2.

The black central doubled pawns are weak, but they temporally act as an important physical wedge in the un-coordinating of the white forces. The white dark square bishop is forced to retreat to a less active square. The march of the queen side pawns has to be postponed. The difference in the functionality between the two sets of doubled pawns is quite remarkable.A possible continuation is 23.Bd2 Ne5 24.Qd1 Qd7 25.Bf4 Qh3 26.Ba2 Rd8 27.Bg3 h5 28.Re1 Rh6 Black has found an alternative route to liberate the king rook. The weakness of the f3, f2 pawns and the lines of attack along the semi-open “g” and closed “h” file now becomes self evident. 29.Rxe5 h4 30.Qf1 hxg3 31.Qxh3 Rxh3 32.Rxd5 gxh2+ 33.Kg2 Rxd5 34.Bxd5 Rh5! = 35.c6 Be5 36.Rd1 Rg5+ 37.Kh1 d3 Diagram 6.

How often in a serious game that you can see five passed pawns?! Black certainly has a good share of the action.Conclusions:Many of the lines have been analysed. So far I cannot see how white can take advantage of 9….Be7!?